W203 C220 CDI Battery Drain

[nkotecha]

Hello Foroum - Firstly happy XMAS to all!

The Wifes car is producing a weird fault, and wanted some pointers please?

This morning, that battery was dead, after 2 days of sitting in the Drive, however it is a new battery!

Made sure nothing was left on (Boot, Glove Doors), however lately i have noticed something weird, and that is when the car running (idling) every 10 seconds the idling would fluctuate (only a small bit) but when that happens the lights also flicker (i hope I am describing this OK)

Now I cannot help but think, there is a charging issue somewhere, but before I start parting with some hard earned cash, wanted to pick your brains - any clues please??

Thanks in advance

Nik

 

[trainer]

Does your wifes car have Comand? My car has a battery drain fault caused by the Comand unit.

 

[nkotecha]

Nope unfortunately she does have Command

 

[jimti]

however lately i have noticed something weird, and that is when the car running (idling) every 10 seconds the idling would fluctuate (only a small bit) but when that happens the lights also flicker (i hope I am describing this OK)

that sounds like a charging problem,(Alternator) but that wouldn't cause the battery to go flat over a couple of days are you sure it was fully charged when it was parked?

 

[nkotecha]

Thanks for this - We only bought the car over a months ago, and the previous owner just put a new battery on HOWEVER it is a Unipart 88AH.

On my diag machine she is holding between 13.4 - 14.2v - when running.

So the question is should I start with the Voltage Regulator on the alternator or should I go for the jugular and change alternator and battery?

Thanks all hardcore MB guys so far

Nik

 

[jimti]

I would start by putting a fully charged battery on the car and see if it looses power over night

 

[nkotecha]

Hi Jimti

Did that last night and she fired up fine this morning - but she still 'flickers' every 10 sec until she reaches abou 75 Degrees Engine Temp - No Faults on Star

 

[jimti]

I am no expert on veh electrics, but I would guess battery is ok, does the rev counter jump at all?

 

[nkotecha]

Yes only a little -

 

[jimti]

that could be a symptom of the alternator starting to fail, I would get it tested before spending money replacing or repairing it though

 

[jaymanek]

W203's have notorious battery drain issues... I wouldnt mess with alternator until you have measured current draw... should be no more than around 200ma after around 5 minutes of doors being locked..

 

[nkotecha]

Thanks for this guys.

However now a litle confused, initially thought about battery/Alternator issue, but it seems from the last thread, that the W203 are a sucker for battery drains. Therefore can Jay please elaborate on what he has found on these elaborate drains.

Again sorry - but I hope that I am not opening a can of worms

Nik

 

[Northerner]

I'm also interested as my C32 is suffering from the same battery drain issues

 

[Stan the Man]

If possible use a ammeter connected in series with the battery in order to measure the quiescent current, should be less than 30mA with all systems shut down.
If quiescent current exceeds 30mA you have excessive battery drain. Attempt isolation by pulling fuses.
Possible culprits include memory seats, comand, overhead control panel and boot lamp.
Good luck.